OFFSET
0,7
FORMULA
EXAMPLE
a(9) = 5; since 9 can be written as the sum of 3 primes in two ways: 2+2+5 = 3+3+3 and the sum of the middle parts of these partitions is 2+3 = 5, we have a(9) = 5.
MATHEMATICA
Table[Sum[Sum[i (PrimePi[i] - PrimePi[i - 1]) (PrimePi[j] - PrimePi[j - 1])(PrimePi[n - i - j] - PrimePi[n - i - j - 1]), {i, j, Floor[(n - j)/2]}], {j, Floor[n/3]}], {n, 0, 80}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Wesley Ivan Hurt, Jun 23 2022
STATUS
approved